Thermoplastic temporary adhesive for silicon handler with infra-red laser wafer de-bonding

ABSTRACT

A bonding material including a phenoxy resin thermoplastic component, and a carbon black filler component. The carbon black filler component is present in an amount greater than 1 wt. %. The carbon black filler converts the phenoxy resin thermoplastic component from a material that transmits infra-red (IR) wavelengths to a material that absorbs a substantial portion of infra-red (IR) wavelengths.

BACKGROUND Technical Field

The present disclosure relates to wafer bonding methods, and morespecifically, to bonding methods including handler wafer de-bonding.

Description of the Related Art

Temporary wafer bonding/de-bonding is an important technology forimplementing the fabrication of semiconductor devices, photovoltaicdevices, and electrical devices of micron and nanoscale. Bonding is theact of attaching a device wafer, which is to become a layer in a finalelectronic device structure, to a substrate or handling wafer so that itcan be processed, for example, with wiring, pads, and joiningmetallurgy. De-bonding is the act of removing the processed device waferfrom the substrate or handling wafer so that the processed device wafermay be employed into an electronic device. Some existing approaches fortemporary wafer bonding/de-bonding involve the use of an adhesive layerplaced directly between the silicon device wafer and the handling wafer.When the processing of the silicon device wafer is complete, the silicondevice wafer may be released from the handling wafer by varioustechniques, such as by exposing the wafer pair to chemical solventsdelivered by perforations in the handler, by mechanical peeling from anedge initiation point or by heating the adhesive so that it may loosento the point where the silicon device wafer may be removed by sheering.

SUMMARY

In one embodiment, a method for forming a semiconductor device isprovided that may include forming a thermoplastic polymeric adhesivelayer including an infra-red (IR) light wave absorbing filler of carbonblack on at least one of a semiconductor containing device substrate anda semiconductor containing handler substrate. The semiconductorcontaining device substrate may be bonded to the semiconductorcontaining handler substrate at a bonded interface through thethermoplastic polymeric adhesive layer including the infra-red (IR)light wave absorbing filler of carbon black. Backside processing may beapplied to the semiconductor containing device substrate, while thesemiconductor containing device substrate is bonded to the semiconductorcontaining handling substrate. The semiconductor containing devicesubstrate may be de-bonded from the semiconductor containing substrateusing an infra-red (IR) laser to ablate at least a portion of thethermoplastic polymeric adhesive layer including an infra-red (IR) lightwave absorbing filler of carbon black from the bonded interface of thesemiconductor containing device substrate and the semiconductorcontaining handler substrate.

In another embodiment, the method for forming the semiconductor devicemay include forming a phenoxy resin adhesive layer including a filler ofcarbon black on at least one of a silicon containing device substrateand a silicon containing handler substrate. The silicon containingdevice substrate may be bonded to the silicon containing handlersubstrate at a bonded interface through the phenoxy resin adhesive layerincluding the filler of carbon black. Backside processing may be appliedto the silicon containing device substrate, while the silicon containingdevice substrate is bonded to the silicon containing handling substrate.The silicon containing device substrate may be de-bonded from thesilicon containing substrate using an infra-red (IR) laser to ablate atleast a portion of the phenoxy resin adhesive layer the filler of carbonblack from the bonded interface of the silicon containing devicesubstrate and the silicon containing handler substrate.

In yet another aspect of the present disclosure, a bonding adhesive isprovided for wafer bonding. In one embodiment, the bonding adhesivecomprises a phenoxy resin thermoplastic components, and a carbon blackfiller component. The carbon black filler component is present in anamount greater than 1 wt. %. The carbon black filler converts thephenoxy resin thermoplastic component from a material that transmitsinfra-red (IR) wavelengths to a material that absorbs a substantialportion of infra-red (IR) wavelengths.

These and other features and advantages will become apparent from thefollowing detailed description of illustrative embodiments thereof,which is to be read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

The disclosure will provide details in the following description ofpreferred embodiments with reference to the following figures wherein:

FIG. 1 is a flow chart illustrating an approach for performingsemiconductor containing handler substrate bonding and de-bonding inaccordance with exemplary embodiments of the present disclosure.

FIG. 2 is a schematic diagram illustrating bonding and de-bonding of asemiconductor containing device substrate to a silicon containinghandler substrate, in accordance with exemplary embodiments of thepresent disclosure.

FIGS. 3A and 3B are schematic diagrams illustrating patterns of applyingthe laser light to a top surface of the semiconductor containing handlersubstrate in accordance with exemplary embodiments of the presentdisclosure.

FIG. 4 is a schematic diagram illustrating a scanning laser de-bondingsystem in accordance with exemplary embodiments of the presentdisclosure.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Detailed embodiments of the claimed compositions and methods aredisclosed herein; however, it is to be understood that the disclosedembodiments are merely illustrative of the claimed compositions andmethods that may be embodied in various forms. In addition, each of theexamples given in connection with the various embodiments are intendedto be illustrative, and not restrictive. Further, the figures are notnecessarily to scale, some features may be exaggerated to show detailsof particular components. Therefore, specific structural and functionaldetails disclosed herein are not to be interpreted as limiting, butmerely as a representative basis for teaching one skilled in the art tovariously employ the methods and structures of the present disclosure.Reference in the specification to “one embodiment” or “an embodiment” ofthe present principles, as well as other variations thereof, means thata particular feature, structure, characteristic, and so forth describedin connection with the embodiment is included in at least one embodimentof the present principles. Thus, the appearances of the phrase “in oneembodiment” or “in an embodiment”, as well any other variations,appearing in various places throughout the specification are notnecessarily all referring to the same embodiment.

For purposes of the description hereinafter, the terms “upper”. “lower”,“right”, “left”, “vertical”, “horizontal”, “top”, “bottom”, andderivatives thereof shall relate to the embodiments of the disclosure,as it is oriented in the drawing figures. The term “positioned on” meansthat a first element, such as a first structure, is present on a secondelement, such as a second structure, wherein intervening elements, suchas an interface structure, e.g. interface layer, may be present betweenthe first element and the second element. The term “direct contact”means that a first element, such as a first structure, and a secondelement, such as a second structure, are connected without anyintermediary conducting, insulating or semiconductor layers at theinterface of the two elements.

In some embodiments, the methods, compositions and structures disclosedherein provide low cost, thermoplastic materials that can be used astemporary, and thin semiconductor substrate-to-semiconductor substrate,e.g., silicon wafer to silicon wafer, bonding-and-laser-de-bondingadhesives, in which at least one of the semiconductor substrates can bea handling substrate (also referred to handling wafer). In someembodiments, a “thin” semiconductor substrate is referred to a substratehaving a thickness ranging from 1 micron to 100 microns, but in otherembodiments the thickness of a thin semiconductor substrate may rangefrom 5 microns to 10 microns. For laser de-bonding, which is one form ofde-bonding technology suitable for use with semiconductor andphotovoltaic manufacturing, a polyimide material is normally used as theadhesive, along with a deep UV excimer laser to ablate the polyimideadhesive layer, which de-bonds the wafer from the wafer handler. Thewafer handler used in accordance with this prior method is typically acoefficient of thermal expansion (CTE) matched glass plate. However, theglass plate has poor thermal conductivity in comparison to silicon (Si).During wafer level test and burn-in, heat dissipation may be a limitingfactor for the use of glass plate as a handler material. In addition,glass substrates are not compatible with the standard electrostaticchucking technology in most semiconductor processing equipment.

In accordance with some of the embodiments of the methods, compositionand structures that are disclosed herein invention, a silicon waferhandling technology is provided in which the handler substrate (alsoreferred to as handler wafer) may not be a glass plate, but is anothersemiconductor substrate, e.g., silicon-containing wafer, such as asilicon (Si) wafer. In these embodiments, the de-bonding step forbreaking the adhesive bond between the semiconductor substrates may beaccomplished with an IR laser and not a deep UV excimer laser. The deepUV (DUV) excimer layer is not suitable for use with some of theembodiments of the methods of the present disclosure, because the lightwavelength emitted by a deep UV excimer laser is absorbed by thesemiconductor material of the semiconductor containing hander substrate.For example, DUV excimer lasers typically emit a wavelength ranging fromin the 150-250 nm range, which are wavelengths typically absorbed bysemiconductor substrate materials, such as silicon (Si).

To transmit through the semiconductor material of the semiconductorcontaining handler substrate, the methods of the present disclosureemploy intra-red (IR) lasers. As used herein, an “infra-red (IR) laser”is a laser that emits light having wavelengths ranging from a lowerlimit with a wavelength on the order of =700-800 nm to an upper limit ofthe visible wavelength range, e.g., approximately 1 mm. Applicantssubmit that light wavelengths within the infra-red (IR) range are notabsorbed by semiconductor materials, such as silicon (Si), which areused in substrates employed in wafer bonding methods, such as handlersubstrates and device substrates.

For typical glass-to silicon bonding technology, the polyimide that iscommon for use in the industry as an adhesive is HD3007, a product fromHD Microsystems, Inc. It has been determined that one disadvantage ofusing a polyimide adhesive material as the adhesive in wafer bondingmethods in microelectronics device manufacturing is the relatively highprocessing temperature that is required to convert the polyimideprecursor, i.e., polyamic acid, to a fully imidized polyimide beforecompleting bonding of the handling wafer to the device wafer. Thetemperature range that is typically used to cure the polyimide toprovide imidization ranges 300° C. to 400° C. In addition, the nature ofa polyimide polymer is usually relatively stiff and rigid such that thepolymer requires a high temperature to soften and bond to the handlingwafer. The high temperatures required for both steps can do damage tosensitive devices that are included in the device wafer. Further, thehigh temperatures required for curing the polyimide for imidization andto soften the polyimide for softening can cause stresses in the devicewafer that induce warping in the device wafer after cooling.Additionally, in order to remove polyimide residues that remain afterde-bonding long soak times in strong hot solvents, such asN-methylpyrrolidone (NMP) and dimethyl sulfoxide (DMSO), may berequired.

In addition, in order for HD3007, and similar composition adhesives, tobe useful to de-bond from semiconductor containing substrate. e.g.,handler wafers composed of silicon (Si), they must be able absorbinfra-red (IR) energy from the laser, which is converted to heat, whichablates the adhesive ablates, just as in the case of the UV laser inprocess flows including a glass handler substrate. It has beendetermined that HD 3007 does not absorb infra-red (IR) wavelength's, andis therefore not suitable for use in bonding methods that employsemiconductor containing substrates, such as silicon containingsubstrates.

It has been determined that in order to impart infra-red (IR) absorptionto the adhesive material, it is required to add an infra-red (IR)absorbing dye or infra-red (IR) absorbing particles, because mostpolymers do not absorb wavelengths of light emitted from infra-red (IR)lasers. In addition to absorbing infra-red (IR) energy, the adhesivemust ablate easily, and be easy to remove in the areas that have not beexposed to de-bonding laser.

In some embodiments, it has been determined that thermoplastic polymerswhen filled with carbon black can be useful for adhesion betweensemiconductor containing substrates, i.e., between a device substratecomposed of a silicon containing material and a handler substratecomposed of a silicon containing material. More specifically,thermoplastic polymers filled with carbon black easily ablate whenexposed to infra-red (IR) energy, i.e., ablated with an infra-red (IR)laser. As will be described in greater detail below, the polymer familysuitable for providing the thermoplastic component of the thermoplasticpolymer filled with carbon black adhesive may be phenoxy, e.g., phenoxyresin filled with carbon black. For example, the phenoxy resin can havea high molecular weight (MW), and may be a linear polymer ofepichlorhydrin and bisphenol A.

In some embodiments, the methods, structures and compositions providedherein provide a set of adhesive resins for use in semiconductorsubstrate to semiconductor substrate bonding and de-bonding processesthat are low cost and have been determined to have good bond/de-bondingperformance for adhesives at lower temperatures than polyimides withoutexhibiting squeeze-out phenomena. In some embodiments, the presentdisclosure provides a method of adhesive bonding that may includebonding a first semiconductor substrate to a second semiconductorsubstrate with an adhesive comprising phenoxy resin, wherein theadhesive is cured at a temperature of less than 300° C. The curedphenoxy resin may have a viscosity greater than 1×10⁵ Pa. Sec.

As used herein, the term “phenoxy resin” denotes a family of BisphenolA/epichlorohydrin linear polymers. Phenoxy resins are typically toughand ductile thermoplastic materials having high cohesive strength andgood impact resistance. The backbone ether linkages and pendant hydroxylgroups promote wetting and bonding to polar substrates. Structurally, insome examples, the phenoxy resin may be polyhydroxyether having terminalalpha-glycol groups. In some embodiments, weight-average molecularweights for the phenoxy resins in accordance with the present disclosuremay range from approximately 10,000 to above 60.000. In on example, thephenoxy resin may have a molecular weight range of 10,000 g/mole to50,000 g/mole. The highest polymeric species of phenoxy resin may exceed250.000 daltons. Olydispersity is very narrow, typically less than 4.0.An average molecule contains 40 or more regularly spaced hydroxylgroups. The phenoxy resin may be a thermoplastic resin suitable for useas an adhesive in low temperature. e.g., less than 300° C. wafer bondingand/or laser de-bonding applications.

In some embodiment of the present disclosure, the phenoxy resin is aPhenoxy Resin PKHC®, PKHH® or PKHJ® having the following formula:

PKHH is available from InChem Corp., in which PKHH phenoxy resin has theIUPAC name: 2-(chloromethyl)oxirane;4-[2-(4-hydroxyphenyl)propan-2-yl]phenol, and chemical formulaC₁₈H₂₁ClO₃. PKHJ and PKHC are also available from InChem Corp. PKHHphenoxy resin has a molecular weight of approximately 52,0000 Mw/13.000Mn (avg.), and has a viscosity ranging from 180-280 cP (Brookfield @ 25°C. 20% in cyclohexanone). PKHJ phenoxy resin may have a molecular weightof approximately 57.0000 Mw/16,000 Mn (avg.), and has a viscosityranging from 600-775 cP (Brookfield @ 25° C. 20% in cyclohexanone). PKHCphenoxy resin may have a molecular weight of approximately 43,0000Mw/11,000 Mn (avg.), and has a viscosity ranging from 410-524 cP(Brookfield @ 25° C. 20% in cyclohexanone).

The carbon black used as the filler in the adhesive of thermoplasticpolymer provides that infra-red (IR) wavelengths emitted by theinfra-red (IR) laser used in the de-bonding process to ablate theadhesive is absorbed by the adhesive. In some embodiments, carbon black(subtypes are acetylene black, channel black, furnace black, lamp blackand thermal black) is a material produced by the incomplete combustionof heavy petroleum products, such as FCC tar, coal tar, ethylenecracking tar, and a small amount from vegetable oil. Carbon black is aform of paracrystalline carbon that has a high surface-area-to-volumeratio, albeit lower than that of activated carbon. The thermoplasticpolymers, e.g., phenoxy resin, when filled with carbon black can absorbwavelengths ranging from 700 nm to 1 mm consistent with the wavelengthsof light emitted from an infra-red (IR) laser, which provides that anadhesive comprised of phenoxy resin filled with carbon black can beablated from a bonded engagement to semiconductor substrates by aninfra-red (IR) laser. Further, in some embodiments in which the releaselayer 24 is present, because the release layer 24 provides thede-bonding performance, the adhesive layer 23 does not require acomposition that can be ablated by an infra-red (IR) laser. Therefore,in this example, not only does the adhesive layer 23 not require thecarbon black filler, the adhesive layer 23 may be composed of adifferent polymer compositions that thermoplastic compositions. Thedetails of the adhesive composition and bonding process in accordancewith the methods, compositions and structures of the present are nowdescribed in greater detail with reference to FIGS. 1 to 4.

FIG. 1 is a flow chart illustrating an approach for performing handlersubstrate bonding and de-bonding in accordance with exemplaryembodiments of the present disclosure. Referring to FIGS. 1 and 2, theadhesive layer 23 may be applied to at least one of the semiconductorcontaining handler substrate 21 and the semiconductor containing devicesubstrate 22 at step 10. The adhesive layer 23 is typically composed ofa thermoplastic resin, e.g., phenoxy resin, in which a filler materialof carbon black within the thermoplastic resin may be incorporated as anadditive to increase absorption of light having wavelengths within theinfra-red (IR) range, such as the wavelengths of light emitted frominfra-red (IR) lasers.

In one embodiment, an adhesive layer 23 may be applied to one of thesemiconductor containing handler substrate 22, and the semiconductorcontaining device substrate 21, and a release layer 24 may be applied tothe other of the semiconductor containing handler substrate 21 and thesemiconductor containing device substrate 22. In this example, both theadhesive layer 23 and the release layer 24 may be composed of anadhesive of a thermoplastic resin. The carbon black filler content inthe adhesive layer 23 and the release layer 24 may be the same, or theamount of the carbon black filler in the adhesive layer 23 may be lessthan the amount of carbon black filler in the release layer 24. In someexamples, the adhesive layer 23 of thermoplastic resin, e.g., phenoxyresin, may be free of carbon black filler.

Referring to FIGS. 1 and 2, in some embodiments, the device substrate 21may be provided by a bulk semiconductor substrate. The bulksemiconductor substrate may have a single crystal, i.e.,monocrystalline, crystal structure. In some embodiments, the devicesubstrate 21 is composed of a silicon including material, such assilicon (Si). In some embodiments, the silicon including material thatprovides the device substrate 21 may include, but is not limited tosilicon, single crystal silicon, multi-crystalline silicon,polycrystalline silicon, amorphous silicon, strained silicon, silicondoped with carbon (Si:C), silicon alloys or any combination thereof. Inother embodiments, the device substrate 21 may be a semiconductingmaterial that may include, but is not limited to, germanium (Ge),silicon germanium (SiGe), silicon germanium doped with carbon (SiGe:C),germanium alloys, GaAs, InAs, InP as well as other III/V and II/VIcompound semiconductors. The thickness of the device substrate 21 mayrange from 5 microns to a few millimeters. In some examples, thethickness of the device substrate 21 may range from 5 microns to 10microns.

The semiconductor containing device substrate 21 may include at leastone semiconductor device. As used herein. “semiconductor device” refersto an intrinsic semiconductor material that has been doped, that is,into which a doping agent has been introduced, giving it differentelectrical properties than the intrinsic semiconductor. In someembodiments, the semiconductor devices that are incorporated into thedevice substrate 21 are field effect transistors (FETs). A field effecttransistor (FET) is a transistor in which output current, i.e.,source-drain current, is controlled by the voltage applied to the gate.A field effect transistor typically has three terminals. i.e., gate,source and drain. The semiconductor devices that may incorporated intothe semiconductor containing device substrate 21 may be planarsemiconductor devices. FinFETS. Trigate semiconductor devices, nanowiresemiconductor devices or a combination thereof. The semiconductordevices present in the semiconductor containing device substrate 21 mayalso include memory devices, e.g., flash memory or eDRAM memory.

The semiconductor containing handler substrate 22 may also be composedof a semiconductor material. For example, the semiconductor containinghandler substrate 22 may be composed of a silicon including material,such as silicon (Si). In some embodiments, the silicon includingmaterial that provides the semiconductor containing handler substrate 22may include, but is not limited to silicon, single crystal silicon,multi-crystalline silicon, polycrystalline silicon, amorphous silicon,strained silicon, silicon doped with carbon (Si:C), silicon alloys orany combination thereof. In other embodiments, the semiconductorcontaining handler substrate 22 may be a semiconducting material thatmay include, but is not limited to, germanium (Ge), silicon germanium(SiGe), silicon germanium doped with carbon (SiGe:C), germanium alloys,GaAs, InAs, InP as well as other III/V and II/VI compoundsemiconductors. The thickness of the semiconductor containing handlersubstrate 22 may range from 5 microns to a few millimeters. In someembodiments, the thickness of the semiconductor containing handlersubstrate 22 may range from 1 micron to 20 microns. In some examples,the thickness of the semiconductor containing handler substrate 22 mayrange from 5 microns to 10 microns.

In one example, the semiconductor containing handler substrate 22 may bea glass substrate.

As noted above, the adhesive layer 23 and the release layer 24 areapplied to at least one of the semiconductor containing device substrate21 and the semiconductor containing handler substrate 22. The releaselayer 24 may be optional. Each of the adhesive layer 23 and the releaselayer 24 may be composed of a thermoplastic resin, such as phenoxyresin, and each of the adhesive layer 23 and the release layer 24 mayinclude carbon black filler. The adhesive layer 23 and the release layer24 may have the same amount of carbon black filler present therein, orthe release layer 24 may have a greater concentration of carbon blackfiller than the adhesive layer 23. In each of the embodiments that aredisclosed herein, whether there is only an adhesive layer 23 thatprovides both the adhesion and de-bonding performance betweensemiconductor containing substrates, or an adhesive layer 23 incombination with a release layer 24, at least one of the material layersat the bonding interface between the semiconductor containing devicesubstrate 21 and the semiconductor containing handler substrate 22includes carbon black filler, in which the carbon black filler absorbsinfra-red (IR) wavelengths to ablate the thermoplastic material, e.g.,phenoxy resin, during the de-bonding process.

The adhesive layer 23 and/or release layer 24 may be composed ofinfra-red (IR) absorbing adhesive material, which can be provided by athermoplastic polymeric adhesive filled with carbon black, wherein thecarbon black introduces absorption properties to the thermoplasticpolymer. In some embodiments, the thermoplastic component of theadhesive layer 23 and/or release layer 24 may be provided with a phenoxyresin. The adhesive layer 23 and/or release layer 24 may be composed ofany of the phenoxy resin compositions that have been described aboveincluding, but not limited to. Phenoxy Resin PKHC®. PKHH® or PKHJ®available from InChem Corp. In one example, the adhesive layer 23 and/orrelease layer 24 may be a phenoxy resin having the chemical name:polyoxy(2-hydrozy-1,3propanediyl)oxy-1,4-phenylene(1-methylethylidene)-1,4-phenylene.

The carbon black that is integrated into the adhesive layer 23 and/orrelease layer 24 as a filler to the thermoplastic component of theresin, e.g., phenoxy resin, introduces infra-red (IR) light waveadsorption properties to the adhesive layer 23 and/or release layer 24.In some embodiments, carbon black can result from the incompletecombustion of carbon-containing materials, such as oil, fuel oils orgasoline, coal, paper, rubber, plastics and waste material. Carbon blacktypically contains greater than 97% elemental carbon arranged asaciniform (grape-like cluster) particulate.

Carbon black may be composed of nodules. i.e., particles, having adiameter ranging from 15 nm to 300 nm. In other embodiments, the carbonblack may be composed of aggregates. In some embodiments, the nearspherical nodules coalesce into particle aggregates that become thebasic indivisible entities of carbon black. Aggregates are composed ofnodules that interact to provide structures having a greatest dimensionranging from 85 nm to 500 nm. Strong electrical forces maintain the bondbetween aggregates and promote the formation of agglomerates, which arethe result of hundreds to thousands of strongly adhering aggregates. Inone embodiment, carbon black agglomerates may have a maximum dimensionranging from 1 micron to 100 microns.

In some embodiments, the carbon black may be integrated into thethermoplastic component. e.g., phenoxy resin, in an amount ranging from1 wt. % to 15 wt. %. In some embodiments, the carbon black may beintegrated into the thermoplastic region. In other embodiments, thecarbon black may be integrated into the thermoplastic in an amount of 4wt. % or less, e.g., ranging from 1 wt. % to 4 wt. %. In other examples,the amount of carbon black filler that may be present in thethermoplastic adhesive, e.g., phenoxy adhesive, may be equal to 1 wt. %,2 wt. %, 3 wt. %, 4 wt. %, 5 wt. %, 63 wt. %, wt. %, 7 wt. %, 8 wt. %, 9wt. %, 10 wt. %, 11 wt. %, 12 wt. %, 13 wt. %, 14 wt. %, and 15 wt. %,as well as, be present in any range comprising any of the aforementionedvalues as a lower limit to the range, and any of the aforementionedvalues as an upper limit to the range.

In some examples, the carbon black filler is integrated into thethermoplastic component of the adhesive, e.g., phenoxy resin, bydissolving the thermoplastic in a solvent, and mixing the carbon blackinto the dissolved thermoplastic and solvent mixture using a high speedmixer. The solvent may be one of ketones, glycol ethers andglycol-esters.

Applying the adhesion layer 23 and/or the release layer 24 may beapplied to the front side surface of the semiconductor containing devicesubstrate 21 and the semiconductor containing handler substrate 22 usinga deposition process, such as spin coating. Typical spin solvents thatare suitable for depositing the adhesion layer 23 and/or the releaselayer 24 using spin coating may include Propylene Glycol Methyl Ether(PGME), Propylene glycol monomethyl ether acetate (PGMEA), ethyllactate, N-Methyl-2-pyrrolidone (NMP) and combinations thereof. In someembodiments, the spin coating solution may further includecyclohexanone.

Spin coating parameters may depend on the viscosity of the adhesionlayer 23 and/or the release layer 24, but may fall in the range fromapproximately 500 rpm to approximately 3000 rpm. One example of a spincoating apparatus for depositing the adhesion layer 23 and/or therelease layer 24 is a fully automated coater system ACS200 from SUSSMicroTec. In one example, a center dispense of the liquid material maybe employed followed by a spread spin at 1000 rpm for 10 seconds. Afterthe spread spin, the material was spun off at 1400 rpm for 60 seconds.It is noted that the above described coating process is only one exampleof a method of depositing the adhesion layer 23 and/or the release layer24 on either of the semiconductor containing device substrate 21 or thesemiconductor containing handler substrate 22, and that other depositionmethods may be suitable for applying the adhesion layer 23 and/or therelease layer 24. For example, the adhesion layer 23 and/or the releaselayer 24 may be deposited using spraying, brushing, curtain coating anddip coating.

In some embodiments, following application of the adhesion layer 23and/or the release layer 24 by spin coating, and prior to the waferbonding step, the spin coated layer of material may be cured. Thesoft-bake may fall in the range from approximately 80° C. toapproximately 120° C. The temperature of the final cure may fall in therange from 200° C. to 400° C. Higher cure temperatures may be moreeffective at ensuring thermal stability of the UV ablation layer duringstandard CMOS BEOL processing which may take place between 350° C. and400° C. For strongly infra-red (IR)-absorbing or infra-red (IR)sensitive materials, very thin final layers on the order ofapproximately 1000 Å to approximately 1 micron thick may be sufficientto act as release layers.

Referring to FIG. 1, following application of the adhesive layer 23and/or the release layer 24, the semiconductor containing devicesubstrate 21 may be bonded to the semiconductor containing handlersubstrate 22 at step 11, such that the release layer 23 and the adhesivelayer 24 are provided between the semiconductor containing devicesubstrate 21 and the semiconductor containing handler substrate 22. Thebonding may include a physical bringing together of the semiconductorcontaining device substrate 21 and the semiconductor containing handlersubstrate 22 under controlled heat and pressure in a vacuum environment,such as offered in any one of a number of commercial bonding tools.

In some embodiments, to provide bonding, temperature and pressure mayapplied to the composite of the semiconductor containing handlersubstrate 22, the adhesion layer 23, the optional release layer 24, andthe semiconductor containing device substrate 21. In one embodiment, thebonding temperature may range between 150° C. to 250° C., and thepressure applied may range from 0.07 MPA to 0.22 MPa. In anotherembodiment, the bonding temperature may range from 175° C. to 200° C.,and the pressure may range from 0.15 MPa to 0.22 MPa. The time period atwhich the bonding temperature and pressure is held may range from 10minutes to 60 minutes. The bonding step may be performed in a nitrogenatmosphere.

Typically, bonding includes elevating the temperature of the releaselayer 24 (when present), and the adhesion layer 23, to effectuate curingof the polymer. In some embodiments, when both the adhesive layer 23,and the release layer 24, phenoxy resin adhesive, such aspolyoxy(2-hydrozy-1,3-propanediyl)oxy-1,4-phenylene(1-methylethylidene)-1,4-phenylene, has a viscosity ranging from100-10,000 Pa. seconds when at a temperature ranging from 160° C. to210° C., and under a pressure of 1000 mbar per area of an 8 inch wafersize for at least one of the device substrate 21 and/or handingsubstrate 22. The viscosity of the phenoxy resin adhesive is at leastone order of magnitude greater than typical adhesives composed ofpolyimides and/or poly(meth)acrylates. In prior adhesives, such aspolyimide and/or poly(meth)acrylates bonding at temperatures below 300°C. resulted in too low a viscosity of the adhesive layer, which resultedin adhesive squeeze out. By providing a higher viscosity with phenoxyresin adhesives, squeeze out of the release layer 23 and/or the adhesivelayer 24 during bonding of the semiconductor containing device wafer 21to the semiconductor containing handler substrate 22 is substantiallyreduced if not eliminated. In some embodiments, the viscosity of thephenoxy resin including the carbon black filler at temperatures rangingfrom 160° C. to 210° C. may range from 1.500-10,000 Pa. second. Inanother embodiment, the viscosity of the phenoxy resin including thecarbon black filler at temperatures ranging from 160° C. to 210° C. mayrange from 2500-10.000 Pa. second. In yet another embodiment, theviscosity of the phenoxy resin including the carbon black filler attemperatures ranging from 160° C. to 210° C. may range from 5000-10.000Pa. second. In one examples, the viscosity of the phenoxy resin attemperatures ranging from 160° C. to 210° C. may be equal to 100, 200,300, 400, 500, 600, 700, 800, 900, 1000, 1500, 2000, 2500, 3000, 3500,4000, 4500, 5000, 5500, 6000, 6500, 7000, 7500, 8000, 8500, 9000, 9500,and 10000 Pa. second, and any range including at least two of the abovenoted values.

Each of the adhesive layer 24, and the release layer 23 (when present),following bonding to the semiconductor containing handler wafer 22, andthe semiconductor containing device substrate 21 may have a shearstrength of 40 MPa or greater.

Another advantage of the present methods is that the curing of thephenoxy resin is at temperatures less than the curing temperatures thatare required of prior adhesives, such as polyimides and/orpoly(meth)acrylates. For example, imidization of polyimides requirestemperatures greater than 300° C., which results in damage to thesemiconductor containing device substrate 21, such a wafer warpageand/or cracking. Additionally, the high temperatures required of prioradhesives composed of polyimides and/or poly(meth)acrylates may alsoresult in unnecessary out diffusion of the dopants of the semiconductordevices that have been integrated into the semiconductor containingdevice substrate 21. Bonding with phenoxy resin is at temperatures below300° C., which is at a temperature that does not damage. i.e., does notcause warping or cracking of the semiconductor containing devicesubstrate 21, and does not cause outdiffusion of the semiconductordevice dopants. In one embodiment, the bonding temperature of thephenoxy resin adhesive may range from 150° C. to 290° C. In anotherembodiment, the bonding temperature of the phenoxy resin adhesive mayrange from 160° C. to 210° C. In other examples, the bonding temperatureof the phenoxy resin may be at 150, 160, 170, 180, 190, 200, 210, 220,240, 250, 260, 270, 280 and 290° C., as well as any range including twoof the aforementioned values.

Referring to FIG. 1, in some embodiments, after bonding to provide thecomposite of the semiconductor containing handler substrate 21, theadhesion layer 23, the optional release layer 24, and the semiconductorcontaining handler substrate 22, the desired processing may be performedto the backside surface of the semiconductor containing device substrate21 at step 12. The backside surface of the semiconductor containingdevice substrate 21 is not engaged to one of the adhesive layer 23 orthe release layer 24. The backside surface of the semiconductorcontaining device substrate 21 is typically opposite the surface of thesemiconductor containing device substrate 21 that the semiconductordevices may be formed on, which may be referred to as the upper surfaceof the semiconductor containing device substrate 21. For example,backside processing may include such process steps as patterning,etching, thinning, etc. until the device wafer has achieved its desiredstate.

For example, in one embodiment, the semiconductor containing devicesubstrate 21 may be thinned by applying a planarization process and/or agrinding process to the backside surface of the semiconductor containingdevice substrate 21. In one example, the planarization and grindingprocess may be provided by chemical mechanical planarization (CMP). Inan alternative embodiment, etch processes may be used to remove materialfrom the back surface of the semiconductor containing device substrate21. Following thinning of the backside surface of the semiconductorcontaining device substrate 21, the thinned semiconductor containingdevice substrate 21 may have a thickness ranging from 5 microns to 100microns In another embodiment, the thinned semiconductor containingdevice substrate 21 may have a thickness ranging from 20 microns to 50microns. In one example, the thinned semiconductor containing devicesubstrate 21 may have a thickness ranging from 5 microns to 10 microns.The semiconductor containing handler substrate 22 supports thesemiconductor containing device substrate 21 during the mechanicalthinning process to protect the semiconductor containing devicesubstrate 21 from mechanical failure, such as cracking.

In another example, the backside processing of the semiconductorcontaining device substrate 21 may include a patterning step to forminterconnects to the semiconductor devices that are integrated withinthe semiconductor containing device substrate 21. For example, viainterconnects, such as through silica vias (TSV), may be formed to theactive regions within the semiconductor containing device substrate 21.Through silica vias (TSV) may be employed to interconnect stackeddevices wafers in forming a three dimensional (3D) microelectronicdevice. Vias can be formed to the active portions of the semiconductorcontaining device substrate 21, using photoresist deposition,lithographic patterning to form a photoresist etch mask, and etching,e.g., anisotropic etching. Following via formation, via interconnectscan formed by depositing a conductive metal into the via holes usingdeposition methods, such as CVD, sputtering or plating. The conductivemetal may include, but is not limited to: tungsten, copper, aluminum,silver, gold and alloys thereof.

After backside processing of the semiconductor containing devicesubstrate 21, a laser ablation process may be performed to sever thesemiconductor containing device substrate 21 from the semiconductorcontaining handler substrate 22 at step 13. During the laser ablationprocess, a laser emits a wavelength of light that is absorbed by atleast one of the release layer 24 (when present), and the adhesive layer23. To be transmitted through the semiconductor containing handlersubstrate 22. e.g., silicon (Si) handler substrate, and/or thesemiconductor containing device substrate 2,1 to expose at least one ofthe adhesive layer 23 and a release layer 24 to the wavelengths of lightbeing emitted from the laser at the bonded interface of thesemiconductor containing device substrate 21 and the semiconductorcontaining handler substrate 22, the wavelength of light being emittedfrom the laser should be within the infra-red (IR) range. Upon exposureto the infra-red (IR) laser light, at least one of the adhesive layer 23and the release layer 24 may burn, break down, or otherwise decompose.In yet other embodiments, the absorption of the infra-red (IR)wavelengths by at least one of the adhesive layer 23 and the releaselayer 24 may cause the layer absorbing the infra-red (IR) wavelengths tomelt. The burning, break down, melting or otherwise decomposition of atleast one the adhesive layer 23 and the release layer 24 is referred toas “ablating” of the material layer with the infra-red (IR) laser.

In one embodiments, infra-red (IR) light is light with a wavelengthranging at a lower limit of the range from ≈700 nm to 800 nm, to awavelength at an upper limit range, which may be 1 mm. Any laseremitting light within these wavelengths can be referred to as infra-red(IR) laser, and are suitable for ablating at least one of the adhesivelayer 23, and the release layer 24, that is present at the bondedinterface between the semiconductor containing device substrate 21, andthe semiconductor containing handler substrate 22. For example, somelaser diodes can emit wavelengths beyond 750 nm. In some embodiments,lasers suitable for laser ablating in accordance with present disclosureinclude lasers that emit light waves in the near-infrared spectralregion (also called IR-A), which may range from ≈700 nm to 1400 nm. Inother embodiments, the infra-red (IR) laser for ablating the releaselayer 24 and the adhesive layer 23 may emit short-wavelength infrared(SWIR, IR-B), which includes light waves extending from 1.4 to 3 μm. Inyet other embodiments, the IR laser for ablating the release layer 24and the adhesive layer 23 may emit mid-infrared (mid-wavelengthinfrared. MWIR, IR-C), which include wavelengths of light that may rangefrom 3 μm to 8 μm. In yet even further embodiments, the IR laser forablating the release layer 24 and the adhesive layer 23 may includelong-wavelength infrared (LWIR, IR-C) ranges from 8 to 15 μm. In someembodiments, the IR laser for ablating the release layer 24, and theadhesive layer 23, may include long-wavelength infrared (LWIR, IR-C)followed by the far infrared (FIR), which ranges to 1 mm and issometimes understood to start at 8 μm.

In some embodiments, the laser for ablating at least one of the releaselayer 24 and the adhesion layer 23 includes Nd:YAG (neodymium-dopedyttrium aluminum garnet; Nd:Y₃Al₅O₁₂) lasers, helium neon (HeNe) lasers,krypton laser, carbon dioxide (CO₂) laser, carbon monoxide (CO) laser ora combination thereof.

Nd:YAG lasers are optically pumped using a flashtube or laser diodes.Nd:YAG lasers typically emit light with a wavelength of 1064 nm, in theinfra-red (IR). However, there are also transitions near 940 nm, 1120nm, 1320 nm. and 1440 nm. Nd:YAG lasers operate in both pulsed andcontinuous mode. Pulsed Nd:YAG lasers are typically operated in theso-called Q-switching mode. In this Q-switched mode, output powers of250 megawatts, and pulse durations of 10 to 25 nanoseconds have beenachieved. Nd:YAG absorbs mostly in the bands between 730-760 nm and790-820 nm. The amount of the neodymium dopant in the material variesaccording to its use. For continuous wave output, the doping issignificantly lower than for pulsed lasers. Some common host materialsfor neodymium are: YLF (yttrium lithium fluoride, 1047 and 1053 nm),YVO₄ (yttrium orthovanadate, 1064 nm), and glass. Nd:YAG lasers andvariants are pumped either by flashtubes, continuous gas dischargelamps, or near-infrared laser diodes (DPSS lasers).

Helium-neon lasers may emit a wavelength of light ranging fromapproximately 1.15 μm to approximately 3.4 μm. A helium-neon laser orHeNe laser, is a type of gas laser whose gain medium consists of amixture of helium and neon (10:1) inside of a small bore capillary tube,usually excited by a DC electrical discharge.

A krypton laser may emit a wavelength of light ranging on the order of750 nm. A krypton laser is an ion laser, a type of gas laser usingkrypton ions as a gain medium, pumped by electric discharge.

Carbon dioxide (CO₂) lasers can emit light wavelengths at 10.6 μm, andsome other wavelengths in that region, e.g., micrometer wavelengthsbeing greater than 9.5 μm. Carbon dioxide (CO₂) lasers are gas lasersthat are one of the highest-power continuous wave lasers, in which theratio of output power to pump power can be as large as 20%. The pumpsource for carbon dioxide (CO₂) lasers may be transverse (high power) orlongitudinal (low power) electrical discharge.

Carbon monoxide (CO) lasers can emit light wavelengths that in someembodiments can range from 2.6 μm to 4 μm, and in some other embodimentscan range from 4.8 μm to 8.3 μm. The pump source for carbon monoxide(CO) lasers may be electrical discharge.

It is noted that the above examples of infra-red (IR) lasers that aresuitable for the methods and adhesive compositions disclosed herein isintended to be illustrative, and is not intended to limit the presentdisclosure, as any number of infra-red (IR) lasers are suitable for usewith the methods and adhesives of the present disclosure, so long as thelaser emits light wavelengths within the above described infra-red (IR)ranges.

As described above, thermoplastic resin, e.g., phenoxy resin, typicallydoes not absorb wavelengths within the infra-red (IR) range. Blackcarbon filler is added to the thermoplastic resin. e.g., phenoxy resin,to provide that the phenoxy resin absorbs the infra-red (IR)wavelengths. In this manner, by adding carbon black filler to thethermoplastic polymer, i.e., phenoxy resin, a release layer 24 composedof thermoplastic polymer, e.g., phenoxy resin, including carbon blackfiller may be provided that when subjected to the wavelengths emitted bythe infra-red (IR) laser is ablated, wherein ablating the release layerde-bonds the semiconductor containing device substrate 21 from thesemiconductor containing handler substrate 22. In some embodiments, whenthe adhesion layer 23 also includes a thermoplastic resin, e.g., phenoxyresin, that also includes carbon black filler, the infra-red (IR) laserthat ablates the release layer 24 may also ablate the adhesive layer 23.In some embodiments, when the adhesion layer 23 does not absorbinfra-red (IR) layer wavelengths, e.g., when the adhesion layer 23 iscomposed of a thermoplastic resin, such as phenoxy resin, that does notinclude the carbon black filler, when the infra-red (IR) laser ablatesthe release layer 24, the adhesive layer 23 may remain hard and engagedto at least one of the semiconductor containing device substrate 21 andthe semiconductor containing handler substrate 22. In some embodiments,when the release layer 24 is omitted, and the adhesive layer 23 iscomposed of a thermoplastic polymer, e.g., phenoxy resin, includingcarbon black filler, ablating the adhesive layer 23 de-bonds thesemiconductor containing device substrate 21 from the semiconductorcontaining handler substrate 22.

Thus, at least one of the release layer 24 and the adhesive layer 23according to exemplary embodiments of the present disclosure comprises amaterial that is broken down under the exposure of the infra-red (IR)laser light. In some embodiments, when the adhesive layer 23 does notinclude carbon black filler, as the adhesive layer 23 may remain hardduring this process, the semiconductor containing device wafer 21, alongwith the adhesive layer 23, may be easily removed from the semiconductorcontaining handler substrate. Where desired, the remainder of theadhesive layer 23 that is not ablated by the infra-red (IR) laser may beremoved from either of the semiconductor containing device substrate 21and the semiconductor containing handler substrate 22 using variousprocessing techniques.

Referring to FIG. 1, after the laser ablation has resulted in thesevering of the semiconductor containing device substrate 21 from thesemiconductor containing handler substrate 22, the semiconductorcontaining device substrate 21 may be easily removed from thesemiconductor containing handler substrate 22, e.g., by simply pullingthe semiconductor containing handler substrate 22 away, and thesemiconductor containing device substrate 21 may be cleaned to removethe adhesive layer 23, or remaining portion of the adhesive layer 23 atstep 14.

In some embodiments, residues of thermoplastic material, e.g., phenoxyresins, that remain on one of the semiconductor containing handlersubstrate 22, and the semiconductor containing device substrate 21,following removal of the release layer 24 may be accomplished using asolvent selected from the group consisting of gamma-butyrolactone, ethyllactate, other lactate isomers known under the tradename Gavesolv, NMP,Tetrahydrofuran (THF), PMAcetate, Methyl isobutyl ketone (MIBK), Methylethyl ketone (MEK), and combinations thereof. Additionally, when theadhesive layer 23 is composed of a thermoplastic material, such asphenoxy resin, the adhesive layer 23 may be removed from thesemiconductor containing handler substrate 22 and/or the semiconductorcontaining device substrate 21 using a solvent selected from the groupconsisting of gamma-butyrolactone, ethyl lactate, other lactate isomersknown under the tradename Gavesolv, NMP, Tetrahydrofuran (THF),PMAcetate, Methyl isobutyl ketone (MIBK), Methyl ethyl ketone (MEK), andcombinations thereof.

FIG. 2 is a schematic diagram illustrating bonding and de-bonding of asemiconductor containing device substrate 21 to a semiconductorcontaining handler substrate 22, in accordance with exemplaryembodiments of the present disclosure. In some embodiments, thesemiconductor containing device substrate 21 may be a silicon substratethat is to be processed, for example, to be added to a three dimensional(3D) stack, such as a layer in a 3D integrated circuit (IC), or an IC tobe included in a 3D package. The semiconductor containing devicesubstrate 21 may be processed prior to bonding, however, prior tobonding the semiconductor containing device substrate 21 may be afull-thickness wafer. The semiconductor containing device substrate 21may be bonded to the semiconductor containing handler substrate 22 toprovide structural support thereto during subsequent processing, whichmay include a thinning of the semiconductor containing device substrate21 to the point where it may no longer poses the structural integritynecessary to withstand certain processing steps that may have to beperformed. The semiconductor containing device substrate 21 need notcomprise silicon and may instead comprise an alternative semiconductormaterial, as described above. The semiconductor containing devicesubstrate 21 may originate as a full-thickness wafer, and maysubsequently be thinned down to a size of between approximately 200 μmand 20 μm.

The semiconductor containing handler substrate 22 may also be composedof a semiconductor material, such as silicon containing material. Insome embodiments, the silicon including material that provides thesemiconductor containing handler substrate 22 may include, but is notlimited to silicon, single crystal silicon, multi-crystalline silicon,polycrystalline silicon, amorphous silicon, strained silicon, silicondoped with carbon (Si:C), silicon alloys or any combination thereof. Inother embodiments, the semiconductor containing handler substrate 22 maybe a semiconducting material that may include, but is not limited to,germanium (Ge), silicon germanium (SiGe), silicon germanium doped withcarbon (SiGe:C), germanium alloys, GaAs, InAs, InP as well as otherIII/V and II/VI compound semiconductors. The semiconductor containinghandler substrate 22 may be sufficiently thick to provide structuralintegrity to the semiconductor containing device substrate 21 bondedthereto. For example, the semiconductor containing handler substrate 22may be approximately 650 μm thick.

As described above, the adhesive layer 23 and the release layer 24 maybe provided between the semiconductor containing device substrate 21 andthe semiconductor containing handler substrate 22. According to oneexemplary embodiment of the present disclosure, the release layer 24 isdisposed directly upon the semiconductor containing handler substrate22.

The release layer 24 may comprise a material that is highly specializedto absorb strongly near the infra-red (IR) wavelength of laser lightused during laser ablation. As exemplary embodiments of the presentdisclosure may employ an infra-red (IR) laser, for example, emittinglight having wavelengths ranging from 700 nm to 1 mm, the release layer24 may comprise a material highly absorbent of infra-red (IR) light, andin particular, light having a wavelength from 1100 nm to 3000 nm. Forexample, the release layer 24 may be comprised of a thermoplastic resin,such as a phenoxy resin. The thermoplastic resin of the release layer 24typically includes carbon filler in a concentration ranging from 1 wt. %to 15 wt. %. The carbon black filler converts the thermoplastic resin,e.g., phenoxy resin, from being a material that does not absorbinfra-red (IR) wavelengths to a thermoplastic resin, e.g., phenoxyresin, that absorbs infra-red (IR) wavelengths in a manner that ablatesthe release layer from the semiconductor containing handler substrate22. For example, the infra-red (IR) wavelengths emitted by the laser andabsorbed by the release layer 24 causes de-bonding primarily throughphotochemical means, by directly breaking chemical bonds in the releaselayer 24 of the carbon black filled thermoplastic, e.g., phenoxy resinfilled with carbon black.

The adhesive layer 23 is present between the release layer 24 and thesemiconductor containing handler substrate 22, and may also have athermoplastic composition. For example, the adhesive layer 23 may becomposed of a phenoxy resin. The phenoxy resin of the adhesive layer 23also include a filler of carbon black similar to the thermoplasticcomposition of the release layer 24. Because the release layer 24 isablated by the infra-red (IR) wavelengths of light emitted by theinfra-red (IR) laser to provide the de-bonding performance, in someembodiments it is not necessary that the adhesive layer 23 include thecarbon black filler that is employed in the release layer 24 to absorbinfra-red wavelengths of light.

In some embodiments, the release layer 24 may be omitted. In thisembodiment, the adhesive layer 23 provides the both the adhesivefunction for bonding the semiconductor containing device substrate 21 tothe semiconductor containing handler substrate 22, as well as thede-bonding function of the release layer 24 (which is omitted). In thisembodiment, it is required that the thermoplastic resin, e.g., phenoxyresin, of the adhesive layer 23 include a filler of carbon black toprovide that the adhesive layer absorbs the infra-red (IR) wavelengthsof light being omitted by the infra-red (IR) laser. For example, thecarbon black filler may be present in a concentration ranging from 1 wt.% to 15 wt. %.

In some embodiments, the adhesive layer 23 and the release layer 24 maybe collectively referred to as at least one bonding layer. As discussedabove, the de-bonding method may employ an infra-red (IR) laser 25 thatmay emit infra-red (IR) wavelengths of light ranging from 700 nm to 1mm. In some embodiments, the infra-red (IR) laser 25 used in accordancewith the present disclosure may have a wavelength ranging from 1000 nmto 5000 nm, a low power level of 100 mJ/cm² or less, and a pulse rateranging from 5 khz to 500 khz. It is noted that the above values areillustrative of only one embodiment of the present disclosure, and isnot intended to limit the present disclosure to only this example. Forexample, the pulse of the laser may cover a wide range, so long as thelaser when applied does not damage the active circuits contained in thedevice wafer.

The release layer 24 may be irradiated though the semiconductorcontaining handler substrate 22, which may not absorb the infra-red (IR)wavelengths of the infra-red (IR) laser 25. The infra-red (IR) laser 25may produce a spot beam that is scanned across the surface of thesemiconductor containing handler substrate 22, for example, in a rasterpattern, or the infra-red (IR) laser 25 may produce a fan beam that isswept once or multiple times across the semiconductor containing handlersubstrate 22. Directing of the light radiated from the infra-red (IR)laser 25 may be handled by the use of a seamier and lens 26.

FIGS. 3A and 3B are schematic diagrams illustrating pattern of applyingthe laser light to a top surface 31 of the semiconductor containinghandler substrate 22 in accordance with exemplary embodiments of thepresent disclosure. As seen in FIG. 3A, the laser light may be directedacross the top surface 31 of the semiconductor containing handlersubstrate 22 as a spot beam drawn to lines 32 which move along an x-axisdirection of the top surface 31 of the semiconductor containing handlersubstrate 22 with each successive line 32 being drawn lower in they-axis direction. Alternatively, as seen in FIG. 3B, the laser light maybe directed in a serpentine pattern 33.

FIG. 4 is a schematic diagram illustrating an apparatus for performinglaser de-bonding in accordance with exemplary embodiments of the presentdisclosure. According to some exemplary embodiments of the presentdisclosure, such as is shown here in FIG. 4, the bonded semiconductorcontaining handler substrate and semiconductor containing devicesubstrate 41 may remain stationary, e.g., on a stage. According to otherexemplary embodiments, the stage may be movable. The infra-red (IR)laser 42 may provide a beam that may then be sent into a beam expander45 to provide the desired beam size. The beam may then enter a scanner46 where the beam can be directed along the x and y axes. One or morecontrol units 43 may affect control of the infra-red (IR) laser 42, beamexpander 45 and the scanner 46. Where the stage upon which the bondedhandler and wafer 41 are held is movable, the controller 43 may controlthe movement of the stage as well. In such a case the scanner 46 may beomitted. A computer system 44 may be preprogrammed with the manner ofcontrol and these instructions may be executed though the one or morecontrol units 43. A scan lens 47 may adjust the beam so as to strike thebonded handler and device wafer 41 with the desired spotcharacteristics.

Methods as described herein may be used in the fabrication of integratedcircuit chips. The resulting integrated circuit chips can be distributedby the fabricator in raw wafer form (that is, as a single wafer that hasmultiple unpackaged chips), as a bare die, or in a packaged form. In thelatter case the chip is mounted in a single chip package (such as aplastic carrier, with leads that are affixed to a motherboard or otherhigher level carrier) or in a multichip package (such as a ceramiccarrier that has either or both surface interconnections or buriedinterconnections). In any case the chip is then integrated with otherchips, discrete circuit elements, and/or other signal processing devicesas part of either (a) an intermediate product, such as a motherboard, or(b) an end product. The end product can be any product that includesintegrated circuit chips, ranging from toys and other low-endapplications to advanced computer products having a display, a keyboardor other input device, and a central processor.

The following examples are provided to further illustrate the presentdisclosure and demonstrate some advantages that arise therefrom. It isnot intended that the disclosure be limited to the specific examplesdisclosed.

Having described preferred embodiments of a system and method foremploying a thermoplastic temporary adhesive for silicon handlersubstrate with infra-red laser wafer bonding, it is noted thatmodifications and variations can be made by persons skilled in the artin light of the above teachings. It is therefore to be understood thatchanges may be made in the particular embodiments disclosed which arewithin the scope of the invention as outlined by the appended claims.Having thus described aspects of the invention, with the details andparticularity required by the patent laws, what is claimed and desiredprotected by Letters Patent is set forth in the appended claims.

What is claimed is:
 1. A bonding material comprising: a phenoxy resinthermoplastic binder; and a carbon black filler component, wherein thecarbon black filler converts the phenoxy resin thermoplastic componentfrom a material that transmits infra-red (IR) wavelengths to a materialthat absorbs a portion of infra-red (IR) wavelengths, wherein the carbonblack is comprised of agglomerates of carbon particles having a size asgreat as 100 microns.
 2. The bonding material of claim 1, wherein thephenoxy resin thermoplastic binder comprises 2-(chloromethyl)oxirane;4-[2-(4-hydroxyphenyl)propan-2-yl]phenol.
 3. The bonding material ofclaim 1, wherein the bonding material being present between twosemiconductor wafers.
 4. The bonding material of claim 1, wherein thebonding material provides an adhesive layer for wafer bonding, or arelease layer for wafer de-bonding.
 5. The bonding material of claim 1,wherein the IR wavelengths absorbed range from 700 nm to 1 mm.
 6. Thebonding material of claim 1, wherein the phenoxy resin is a linearpolymer of epichloryhdrin and bisphenol A.
 7. The bonding material ofclaim 1, wherein the phenoxy resin has a molecular weight rang of 10,000g/mole to 50,0000 g/mole.
 8. The bonding material of claim 1, whereinthe carbon black filler is present in amounts as great as 15 wt. %. 9.The bonding material of claim 1, wherein the phenoxy resin thermoplasticbinder comprises polyoxy(2-hydrozy-1,3propanediyl)oxy-1,4-phenylene(1-methylethylidene)-1,4-phenylene.
 10. Thebonding material of claim 1, wherein the carbon black comprises anaciniform particulate.
 11. A bonding material comprising: a phenoxyresin thermoplastic binder; and a carbon black filler component, whereinthe carbon black filler converts the phenoxy resin thermoplasticcomponent from a material that transmits infra-red (IR) wavelengths to amaterial that absorbs a portion of infra-red (IR) wavelengths, whereinthe carbon black is comprised of agglomerates of carbon particles havinga size as great as 100 microns, wherein viscosity of the bondingmaterial at temperatures ranging from 160° C. to 210° C. may range from5000 Pa. sec to 10,000 Pa. sec.
 12. The bonding material of claim 11,wherein the phenoxy resin thermoplastic binder comprises2-(chloromethyl)oxirane; 4-[2-(4-hydroxyphenyl)propan-2-yl]phenol. 13.The bonding material of claim 11, wherein the bonding material beingpresent between two semiconductor wafers.
 14. The bonding material ofclaim 11, wherein the bonding material provides an adhesive layer forwafer bonding, or a release layer for wafer de-bonding.
 15. The bondingmaterial of claim 11, wherein the IR wavelengths absorbed range from 700nm to 1 mm.
 16. The bonding material of claim 11, wherein the phenoxyresin is a linear polymer of epichloryhdrin and bisphenol A.
 17. Thebonding material of claim 11, wherein the phenoxy resin has a molecularweight rang of 10,000 g/mole to 50,0000 g/mole.
 18. The bonding materialof claim 11, wherein the carbon black filler is present in amounts asgreat as 15 wt. %.
 19. The bonding material of claim 11, wherein thephenoxy resin thermoplastic binder comprises polyoxy(2-hydrozy-1,3propanediyl)oxy-1,4-phenylene(1-methylethylidene)-1,4-phenylene.
 20. Thebonding material of claim 11, wherein the carbon black comprises anaciniform particulate.